High flow EGR system

Abstract

A high flow EGR system for an internal combustion engine having a pair of series connected EGR coolers and a water droplet condensation collector and reservoir connected to the gas flow. The reservoir feeds a pump which is actuated to inject the liquid to the engine adjacent each cylinder for uniform distribution of the water to the engine cylinders. The pump is controlled to inject the water at appropriate conditions during the engine operating cycle.

1. An exhaust gas recirculation (EGR) system for introducing significant quantities of exhaust gas into the intake of an air-breathing, fuel-consuming, multi-cylinder internal combustion (IC) engine having an exhaust for products of combustion and an intake for combustion air, said system comprising:
 a passage connecting the exhaust of said IC engine to its intake; 
 a valve for controlling flow of exhaust through said passage; 
 at least one EGR heat exchanger interposed in said passage for cooling to a significant extent the gas passing therethrough thus resulting in condensation; 
 a collector downstream of said heat exchanger for collecting the condensation from the gas stream; 
 a pump connected to said collector; and 
 a plurality of injectors connected to the output of said pump for uniform distribution of flow to the air intakes for said cylinders of said IC engine. 
 
     
     
       2. The EGR system of  claim 1  having an injector for each cylinder of said multi-cylinder engine. 
     
     
       3. The EGR system of  claim 1  including a pair of EGR coolers. 
     
     
       4. The EGR system of  claim 1  further including an intake air cooler upstream of the point at which said passage connects the exhaust of the IC engine to its intake. 
     
     
       5. The EGR system of  claim 4  wherein the intake cooler is an air-to-air intercooler. 
     
     
       6. The EGR system of  claim 1  further including a control for said pump. 
     
     
       7. The EGR system of  claim 6  wherein said pump is controlled to controllably inject when the engine power output is rapidly increased. 
     
     
       8. The EGR system of  claim 6  wherein said pump is controlled to inject when the engine power output are above a light load. 
     
     
       9. The EGR system of  claim 8  further including a reservoir and a level sensor in said reservoir for sensing the quantity of liquid in said reservoir. 
     
     
       10. A power system comprising:
 a air-breathing, fuel-consuming, multi-cylinder internal combustion (IC) engine having an exhaust for products of combustion and an intake for combustion air; 
 a passage connecting the exhaust of said IC engine to its intake; 
 a valve for controlling flow of exhaust gasses through said passage; 
 at least one EGR heat exchanger in said passage for significant cooling of the gasses flowing therethrough for promoting condensation of moisture droplets; 
 a collector downstream of said heat exchanger for collecting the condensation; 
 a pump connected to said collector; and 
 a plurality of injectors connected to said pump for uniform distribution of liquid to said cylinders. 
 
     
     
       11. The power system of  claim 10  having a water injector for each cylinder. 
     
     
       12. The power system of  claim 10  further including a pair of EGR coolers. 
     
     
       13. The power system of  claim 10  further including an intake air cooler upstream of said passage connecting the exhaust of the IC engine to its intake. 
     
     
       14. The power system of  claim 13  wherein said intake air cooler is an air-to-air after cooler. 
     
     
       15. The power system of  claim 10  further comprising a control for said pump. 
     
     
       16. The power system of  claim 15  wherein said pump is controlled to inject when the engine power output is above a light load. 
     
     
       17. The power system of  claim 16  further comprising a reservoir for condensed liquid and a level sensor. 
     
     
       18. The power system of  claim 16  wherein said pump is controlled to inject when the engine power output is above a load approximately 20% of the maximum engine power.